Investigation of Diameter and Height Growth of Willow and Alder in Road Fill-Slope Landslide Bioengineering Stabilization (Surdar-Watashan District Chamestan, Mazandaran)

The aim of this study was to evaluate the diameter and height growth of two native species of alder (Alnus glutinosa L. Gaertn.) and willow (Salix alba L.) planted in three treatments including natural mulches of straw, wood chips and bare soil without mulch (as control) treatments. The design of the experiments was in the form of split plots and in the form of completely random blocks located in Chamestan, Mazandaran. The results showed that the regression relationships between diameter and height in alder species were better than those of willow species completely randomly. The study area was in parcels 5 of series 3 district of Surdar -Watashan forestry plan in watershed 49 of forests in the north of the country. The regression coefficient for the independent variable of diameter and dependent variable of height was 0.65 in alder and 0.42 in willow. The results showed that the regression relationship between diameter and height in alder was better than willow species. According to the results of variance analysis, the blocks and treatments did not have a statistically significant difference. The wood chips treatment created the best situation, and after that, the straw treatment and finally the control treatment (bare soil) had a more unfavorable situation than the other treatments. Finally, alder had more favorable conditions for adaptation to the applied bioengineering conditions of the present study vs. willow.